The Benchmark Results - Transfer Rate Of Spanning

As already said, 'spanning' means that FastTrak66 creates one large drive out of the drives connected to it, by hanging one after the other. With RAID 0 you also get one large drive, but its size is determined by the smallest drive in the array. This is not the case with spanning. There is no reason or sense to use spanning unless the sizes of the hard drives are very different. If the sizes are close or even identical, you should always use striping instead, because it supplies almost or exactly the same capacity as spanning, but a multiple of its bandwidth.

You can nicely see how one drive comes after the other. The performance is exactly the same as the performance of a single drive. The only advantage of spanning is that you don't have to fight with several logical drives in your system, which can often make it difficult to find something. Spanning makes one logical drive out of 2 - 4 physical ones.